This invention relates in general to copy protection and, more specifically, to copy protection of terrestrial broadcast digital television.
Copy protection and digital rights management (DRM) are used to protect content from use not licensed by the copyright holder. There are various levels of protection which include copy freely, copy once, copy never, etc. Protection of movies and music on the Internet has been performed with DRM. In some cases, software is also protected with DRM.
Digital television (DTV) is broadcast in many designated marketing areas (DMA). One popular type of DTV is high-definition television (HDTV). Some televisions include DTV tuners, while others rely on external tuners. Anyone with a tuner can receive and view the broadcast programs. These broadcasts are transmitted in the clear, but may include a flag that indicates the program should not be copied. The flag is also in the clear, but is intended to secure the program. A properly-functioning DTV tuning device recognizes the flag and prevents copying to the extent possible. Those skilled in the art can appreciate that the flag could easily be replaced by a content pirate to make the program unsecured. Conventional DTV is referred to as unprotected DTV in this application. Further, many other techniques can be used to pirate or steal the broadcast programs.
In the United States alone there are hundreds of millions of TV sets that may move to various geographic locations during their lifetime. Today, most of these TVs are analog, but the trend is toward use of TVs and external tuners that can receive unprotected DTV. A given broadcaster in a particular DMA only needs to worry about those TVs that can receive the signal, but the owners can move from one DMA to another DMA along with his or her TV.
In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.